Pressure-regulating valve



May 30, 1967 A. F. ENEMARK V PRESSURE-REGULATING VALVE I Filed Feb. 11, 1964 m 6 F 5 .2 w m 4/ w n A I I 0 147 M12 .1 Hm M United States Patent Office 3,322,134 Patented May 30, 1967 3,322,134 PRESSURE-REGULATING VALVE Ame F. Enemark, Sonderborg, Denmark, assignor to Danfoss ved ing. M. Clansen, Nordhorg, Denmark, :1 company of Denmark Filed Feb. 11, 1964, Ser. No. 343,974 Claims priority, a plication Germany, Feb. 20, 1963, D 40,941 9 Claims. (Cl. 137-108) This invention relates generally to fluid pressure systems comprising a controlled portion in which a constant output pressure is maintained and more particularly to a pressure-regulating valve for such systems.

Pressure regulated systems in which it is desired to maintain a constant output pressure, for example in fuel oil pump systems for oil burning apparatus, pressure-regulating valves are employed to return a portion or fraction of the discharge of a pump to the system upstream of the pump or on the suction side thereof. Such systems provide for varying the quantity of fluid return from the discharge side of the input side in dependence upon pressure variations in the output side of the fluid pressure source, for example the pump.

In fluid pressure systems of this type and more particularly in fuel oil pump systems, two types of controlled systems are generally employed. The first type of system is where the fuel oil tank is disposed above the level of the pump so that a constant positive pressure is maintained on the suction side of the pump and there is substantially no danger of entrapping or entraining air through the suction side of the pump since the system between the fuel oil tank and the pump is constantly under pressure. In such cases the pressure-regulating valves in the system generally provide for fluid return along a single return line to the suction side of the pump.

The second type of system is one in which the fuel oil source, for example the tank, is below the level of the pump and in order to obtain fuel flow the pump will create a pressure drop in a line between the suction side of the pump and the tank in which case there is a possibility of entrapping air in the system. The system gen erally provides for fuel oil return to the suction side of the pump along two lines, one to the suction side of the pump and another to the fuel oil source, the tank, in order to preclude the possibility of an air lock in the system. These two types of systems will be referred to hereinafter respectively as a one-line system and a two-line system.

Systems are also known in which a pressure-valve is disposed in a cross connecting branch of the system within the connecting lines in the system such that the system will operate as a two-line system during the initial phases of operation and as a single-line system once a positive pressure is ensured between the pump and the tank. Such valves automatically convert the system to a one-line or a two-line system and cause a change-over in the system from a one-line system to a two-line system. In the event that the pressure-valve fails such systems are constructed to be rendered inoperative although the other component parts are in an operative condition.

It is a principal object of the present invention to provide an oil pump installation or system with automatic operation and easy change-over or installation in a oneline or a two-line operation and which secures correct initial starting operation in either type of system.

A feature of the present invention is the provision of a new and improved pressure-regulating valve which is conunder pressure, for example a pump, which takes a suction from a source of incompressible fluid, for example a fuel tank. The pressure-regulating valve comprises a housing defining a bore comprising a valve chamber and in which is disposed a valve member actuated reciprocably in response to fluid received under pressure in the valve chamber at an inlet opening therein so that the valve member is capable of opening and closing simultaneously two outlets in communication with the chamber to return fluid under pressure to a suction side of the source of fluid under pressure and to allow fluid under pressure to flow directly to the initial source, for example the tank. The two outlets are of equal cross section or area and are opened concurrently in direct proportion to the pressure of the fluid under pressure received in the chamber since the valve member is biased in a direction for closing the two outlets by a spring when the fluid pressure in the chamber is below a given pressure level. The given pressure level, of course, determines the control point at which the incoming pressure will effectively open or close the two outlets.

Another feature of the invention is the provision of a cut-off valve in the same housing as the new and improved pressure-regulating valve.

The pressure-regulating valve according to the invention makes provision for being used in a single-line or a two-line fuel oil system and for functioning in installations or systems in which a fluid pressure seal is maintained on the pump itself.

Other features and advantages of the pressure-regulating valve in accordance with the present invention will be better understood as described in the following specification and appended claims, in conjunction with the following drawings in which:

FIG. 1 is a schematic diagram of a fuel oil system in which a pressure-regulating valve according to the invention is employed and illustrated diagrammatically in section; and

FIG. 2 is a sectional longitudinal view of a second embodiment of a pressure-regulating valve according to the invention and provides a cut-off valve.

Although the invention will be described as applied to a fuel oil system in which a constant pressure is maintained as a nozzle or burner, it will be understood that the invention is equally applicable to all types of incompressible fluid pressure systems having a source of incompressible fluid and a source of incompressible fluid under pressure connected in operation for taking a suction from the first mentioned source and in which a constant pressure is desired to be maintained downstream of the source of fluid under pressure by the return of a portion or fraction of the output of the source of fluid under pressure to an upstream or suction side of the pressure source.

Moreover, while the invention will be described as embodied in pressure-regulating valves having their own respective valve housings and connected through line connections to a controlled system, it will be understood that pressure-regulating valves according to the invention can be made as an integral part of a pump in which the operative members are housed, for example in a pump housing or casting, not shown.

According to the drawing, a fuel oil pump 1 takes a suction from a fuel oil tank 2, connected for example, at a level lower than the pump through a suction line 3. The fuel oil under pressure is delivered by the pump through a discharge line 4 through a cut-off valve 5 to a burner or nozzle 6 at which it is desired to maintain a constant pressure. The cut-off valve 5, in this illustration, is of known type which shuts off delivery to the burner 6 when the pressure in the line 4 is reduced below a given pressure level, for example, if the pump 1 is stopped. A return line 7 connects a pressure-regulating valve 8, according to the invention, to the pressure line 4 upstream of the cut-off valve 5 and the burner 6 which is the portion of the fuel oil system to be controlled and maintained at a constant pressure.

The pressure-regulating valve 8 comprises a valve housing as illustrated having inside walls or surfaces defining a bore therein in which is reciprocably mounted a spool or valve plunger 9 reciprocably mounted in the bore and having two axially spaced portions with enlarged diameters as illustrated. The enlarged portions of the spool or plunger 9 define in conjunction with the inner walls of the bore a fluid chamber for receiving therein the incompressible fluid or fuel oil under pressure from the return line 7. A space 10 defined by the plunger and the bore walls also provided with an inlet as illustrated is connected through a branch line providing communication with the return line '7. The fluid under pressure in the space 10 applies fluid pressure to an end face of the plunger or piston 9.

A spring 11 internally of the bore biases the plunger 9 against the fluid pressure applied through the return line 7 and the branch line, as illustrated into the compartment or space 10 by acting on an end face of the plunger or spool opposite to that subjected to fluid pressure in the space 10. The spring 11 biases the spool in a direction for causing a surface 12 on an enlarged portion of the spool to close two outlets 13, 14 formed in the valve and in communication with the pressure chamber defined in the bore between the two enlarged portions of the spool 9 and the valve inner walls. These two outlets 13, 14 are disposed in the same plane and have equal flow areas or cross sections.

The outlet 13 is connected to a return line 15 for returning fluid under pressure as hereinafter described, to the fuel oil supply tank 2. The other outlet 14 is connected to a pressure line 16 which is connected to a packing box 17 on the suction side of the pump to effectively cause a fluid seal therein in known manner when the outlet is open. A short branch line is connected from the packing box 17 to the line 3 as illustrated and in which is provided a pressure-responsive non-return valve 18. A line 19 is provided between the return line 16 and an outlet or opening into a space in which the spring 11 is housed as illustrated. This line 19 allows fluid flow out of the space 20. It will be understood that fluid flow into and out of the spaces 10 and 20 takes place as'the spool or plunger 9 is actuated axially as the two oppositely disposed outlets 13, 14 are covered and uncovered or opened and closed as hereafter described.

An adjust screw or plug 21 externally threaded is provided for setting a control point at which a given or selected pressure applied by fluid under pressure to the plunger 9 overcomes the spring 11 and the surface 12 is moved axially into a position in which the two outlets, 13, 14 are opened or uncovered an equal amount to allow equal fluid flow therethrough and determined in dependence upon the fluid pressure applied from the discharge line 4.

In the system illustrated when the non-return valve 18 opens, or if it fails and remains constantly open, the return flow from the pump 1 is returned to the system to the suction side of the pump through the line 16. Thus, in the system illustrated, the connections are set up for a two-line system and the valve 18 can be adjusted to make the system shift from one type of operation to the other, namely from a one-line system to a two-line system and vice versa.

The valve illustrated in FIG. 1 can be used in both necessary to the system. Thus, the pressure regulating valve according to the invention provides a pressureregulating valve capable of being used either with a oneline return or a two-line return system, the latter of'which is illustrated.

In the second embodiment, FIG. 2, of a pressure-regulating valve according to the invention the valve is supplied with an incompressible fluid under pressure through I an inlet or passageway along a flow path designated by an arrow 4 corresponding to a fuel oil supply path from a pressure line from a source of pressure fluid, such as the discharge line 4 in the first embodiment described. For ease of reference the drawing has the elements in the second embodiment comparable to FIG. 1 designated with similar primed reference numerals. The valve comprises an outlet for discharging fluid at a substantially constant pressure to a controlled portion of a system, not shown, along a flow path illustrated by an arrow 6 to a point in the system where it is desired to maintain a constant pressure, for example to a nozzle, not shown, such as the burner or nozzle '6. The housing is provided with an axial bore in which is reciprocably disposed a valve member or piston 9 actuated axially in a direction against the pressure applied thereto by incoming fluid pressure by a control spring 11'. A face surface 12' of the valve member 9' effectively opens and closes two outlets 13', 14 confronting each other and in a common plane and both of equal flow area for discharging fluid under pressure along paths corresponding to the lines designated by the arrows 15', 16' corresponding to the two lines 15 and 16 of the first embodiment for returning fluid to the suction side of a pump and to a tank, not shown, in the system in which the valve is connected as before described.

An internal passageway 19 corresponding to the line 19 provides communication from the outlet or passageway 14 for fluid flow to a space 20, corresponding to the space 20 in FIG. 1, so that fluid under pressure is provided on the other side of the valve body 9' from which the spring 11' is disposed. The spring force is adjustable by threaded screw 21 in conjunction with a ball 27 as illustrated for determining the control point of the variable to be controlled.

The chamber intowhich the fluid under pressure is received comprises a chamber 22 defined by the piston or plunger 9- and the walls defining the valve axial bore and in which a passageway or outlet 23 is disposed for flow along the flowpath6' and circumferentially of which is provided a seat 24 for seating thereon anaxial projection 25 integral with the valve plunger 9 and adapted to function as a cut-off valve whenever the pressure drops internally of the chamber 22, for example if the pump or pressure source is turned off, sufliciently for the spring 11 to seat the projection 25 on the valve seat 24. It will be understood, that the chamber 22 corresponds to the pressure chamber between the enlarged portions of the spool or plunger 9 in the first embodiment.

'When the pump is operating, the fluid under pressure inside the space or chamber 22 urges the valve member 9 against the force of the spring 11. If the pressure is sufliciently high, the valve piston 9' is actuated axially sufliciently to unseat the cut-off valve 25 and to open the outlets or ports 15, 14 an equal amount in variably adjusting in an axial position in dependence upon the pressure in the chamber 22 to maintain a substantially constant pressure to the outlet 23 providing the required control of fuel oil at a substantially constant pressure downstream of the pressure source, for example to a burner not shown, as indicated heretofore.

Those skilled in the art will readily understand that the valves according to the invention can be made integral with the various passageways and chambers formed in a pump or casting thereof, not shown.

While preferred embodiments of the invention have been shown and described, it will be understood that many modifications and changes can be made within the true spirit and scope of the invention.

What I claim and desire to secure by Letters Patent is:

1. For use in a fluid pressure system having a source of fluid and a source of fluid under pressure connected in operation for taking a, suction from the first-mentioned source, an improved pressure-regulating valve connected in operation in a portion of said system which is to be controlled and the pressure maintained constant therein and downstream of said source of fluid under pressure on a discharge side thereof comprising, means defining a bore comprising a valve chamber and having an inlet in communication with said chamber for receiving fluid under pressure from the second mentioned source and two outlets in a same plane in communication with said chamber for connection in operation with said first mentioned and second mentioned fluid sources respectively to return fluid under pressure to a suction side of said second mentioned source and to allow fluid under pressure to flow directly to said first mentioned source, said outlets being disposed on different sides of said chamber and having equal flow areas, a valve member in said bore responsive to fluid under pressure and actuatable in response to fluid under pressure in said chamber for opening said two outlets simultaneously an equal amount in direct proportion to fluid pressure increases over a given selected pressure, and means for causing said valve member to close said two outlets in dependence upon the pressure in said chamber and for causing complete closing of said two outlets when said fluid pressure in said chamber is below said selected pressure.

2. For use in a fluid pressure system having a source of fluid and a source of fluid under pressure connected in operation for taking a suction from the first mentioned source, an improved pressure-regulating valve connected in operation in a portion of said system which is to be controlled and the pressure maintained constant therein downstream of said source of fluid under pressure on a discharge side thereof comprising, means defining a valve chamber and having an inlet in communication with said chamber for receiving fluid under pressure from the second mentioned source and two outlets in communication with said chamber, one of said outlets for connection in operation with said first mentioned fluid source to return fluid under pressure to a suction side of said second mentioned source the other of said outlets alternatively closeable or connectable in operation to allow fluid under pressure to flow directly to said first mentioned source, said outlets being disposed on different sides of said chamber and having equal flow areas, valve member reciprocable in said bore responsive to fluid under pressure and actuatable in response to fluid under pressure in said chamber for opening said two outlets simultaneously in direct proportion to fluid pressure increases over a given selected pressure, and means for causing said valve member to close said two outlets in dependence upon the pressure in said chamber and for causing complete closing of said two outlets when said fluid pressure in said chamber is below said selected pressure.

3. For use in a fluid pressure system having a source of fluid and a source of fluid under pressure connected in operation for taking a suction from the first mentioned source, an improved pressure-regulating valve connected in operation in a portion of said system which is to be controlled and the pressure maintained constant therein and downstream of said source of fluid under pressure on a discharge side thereof comprising means defining a bore comprising a valve chamber and having an inlet in communication with said chamber for receiving fluid under pressure from the second mentioned source and two outlets in a same plane of equal cross section in communication with said chamber for connection in operation with said first mentioned and second mentioned fluid sources respectively to return fluid under pressure to a suction side of said second men-tioned source and to allow fluid under pressure to flow directly to said first mentioned source, said outlets being disposed on different sides of said chamber and having equal flow areas, a valve member responsive to fluid under pressure and actuatable in response to fluid under pressure in said chamber for opening said two outlets concurrently equal amounts in direct proportion to fluid pressure increases over a given selected pressure, and means for causing said valve member to close said two outlets concurrently equal amounts in dependence upon the pressure in said chamber and for causing complete closing of said two outlets when said fluid pressure in said chamber is below said selected pressure.

4. A pressure-regulating valve according to claim 3, having a third outlet in communication with said chamber, and a projection on said valve member for closing said third outlet when said valve member closes said two outlets concurrently, and said third outlet connectable in operation to said controlled portion of said system in which pressure is to be maintained constant for isolating said portion when said fluid pressure is below said selected pressure.

5. A pressure-regulating valve according to claim 3, in which said valve member comprises a valve spool reciprocable in said bore.

6. A pressure-regulating valve according to claim 5, in which the last mentioned means comprises a spring biasing said spool against fluid under pressure in said chamber.

7. A pressure-regulating valve according to claim 3, in which said valve member comprises a spool reciprocable in said bore, said spool having two axially spaced portions with enlarged diameters, one of said portions being effective to cover said outlets thereby to close said two outlets and effective to uncover said outlets thereby to open said two outlets, said two outlets being disposed intermediate said two portions when said spool uncovers them, said valve having the first mentioned inlet for receiving fluid under pressure internally of said valve bore from said source of fluid under pressure opening into said bore intermediate of said two portions, said valve having an inlet for receiving fluid under pressure in said bore for applying pressure to an end face of said spool in a direction for opening said two outlets and opposite to force applied by the last mentioned means, and the last mentioned means comprising a spring biasing said spool in a direction for closing said two outlets.

8. A pressure-regulating valve according to claim 7, in which said spring is disposed in a space in said bore applying pressure to an end face of said spool at an end opposite to the first mentioned face, and said valve including an opening into said space for connecting thereto said outlet connectable to return fluid to a suction side of said second mentioned source.

9. In a fluid pressure system having a source of fluid and a source of fluid under pressure connected in operation for taking a suction from the first mentionedsource, an improved pressure-regulating valve connected in operation in a portion of said system which is to be controlled and the pressure maintained constant therein, downstream of said source of fluid under pressure on a discharge side thereof comprising means defining a bore comprising a valve chamber, and having an inlet in com munication with said chamber for receiving fluid under pressure from the second mentioned source and two outlets in a same plane in communication with said chamber connected in operation with said' first mentioned and second mentioned fluid sources respectively to return fluid under pressure upstream of second mentioned source and to allow fluid under pressure to flow directly to said first mentioned source, said outlets being disposed on different sides of said chamber and having equal flow areas, a valve member reciprocable in said chamber responsive to'fluid under pressure and actuatable in response to fluid under pressure in said chamber for opening said two outlets concurrently equal amounts in direct proportion to fluid pressure increases over a given selected pressure, and means causing said valve member to close said two outlets in dependence upon the pressure in said chamber and for causing complete closing of said two outlets when said fluid pressure in said chamber is below said selected pressure.

References Cited UNITED STATES PATENTS 6/1956 Heard 137--1l6 5/1961 Livermore 103-42 10/1961 Eames 103-42 X 12/1961 Hansen 137 -116 1/1962 Malmstrom et a1. 239-126 3/1962 Christenson 137-115 X FOREIGN PATENTS 2/1944 Great Britain.

WILLIAM F. ODEA, Primary Examiner.

15 DAVID R. MATTHEWS, Assistant Examiner. 

1. FOR USE IN A FLUID PRESSURE SYSTEM HAVING A SOURCE OF FLUID AND A SOURCE OF FLUID UNDER PRESSURE CONNECTED IN OPERATION FOR TAKING A SUCTION FROM THE FIRST-MENTIONED SOURCE, AN IMPROVED PRESSURE-REGULATING VALVE CONNECTED IN OPERATION IN A PORTION OF SAID SYSTEM WHICH IS TO BE CONTROLLED AND THE PRESSURE MAINTAINED CONSTANT THEREIN AND DOWNSTREAM OF SAID SOURCE OF FLUID UNDER PRESSURE ON A DISCHARGE SIDE THEREOF COMPRISING, MEANS DEFINING A BORE COMPRISING A VALVE CHAMBER AND HAVING AN INLET IN COMMUNICATION WITH SAID CHAMBER FOR RECEIVING FLUID UNDER PRESSURE FROM THE SECOND MENTIONED SOURCE AND TWO OUTLETS IN A SAME PLANE IN COMMUNICATION WITH SAID CHAMBER FOR CONNECTION IN OPERATION WITH SAID FIRST MENTIONED AND SECOND MENTIONED FLUID SOURCES RESPECTIVELY TO RETURN FLUID UNDER PRESSURE TO A SUCTION SIDE OF SAID SECOND MENTIONED SOURCE AND TO ALLOW FLUID UNDER PRESSURE TO FLOW DIRECTLY TO SAID FIRST MENTIONED SOURCE, SAID OUTLETS BEING DISPOSED ON DIFFERENT SIDES OF SAID CHAMBER AND HAVING EQUAL FLOW AREAS, A VALVE MEMBER IN SAID BORE RESPONSIVE TO FLUID UNDER PRESSURE AND ACTUATABLE IN RESPONSE TO FLUID UNDER PRESSURE IN SAID CHAMBER FOR OPENING SAID TO OUTLETS SIMULTANEOUSLY AN EQUAL AMOUNT IN DIRECT PROPORTION TO FLUID PRESSURE INCREASES OVER A GIVEN SELECTED PRESSURE, AND MEANS FOR CAUSING SAID VALVE MEMBER TO CLOSE SAID TWO OUTLETS IN DEPENDENCE UPON THE PRESSURE IN SAID CHAMBER AND FOR CAUSING COMPLETE CLOSING OF SAID TWO OUTLETS WHEN SAID FLUID PRESSURE IN SAID CHAMBER IS BELOW SAID SELECTED PRESSURE. 